1. Technical Field
The disclosure relates to a host-guest complex or an interlocked molecule, especially a pseudorotaxane, a rotaxane or a catenane.
2. Description of Related Art
Pseudorotaxanes, rotaxanes and catenanes are becoming increasingly important materials for gelation, drug delivery, and molecular electronics; therefore, efforts continue toward developing new threading systems and new methods to synthesize these intertwined and interlocked molecules. Although many elegant interlocked molecular compounds and threaded supramolecular complexes have been prepared in the past two decades, the number of recognition motifs that can be exploited for the preparation of these systems remains limited. This difficulty arises mainly from the limited ability to incorporate suitable recognition units in an appropriate arrangement in the molecular structures of the host and guest components, so that weak noncovalent interactions can collaborate together to stabilize the resulting pseudorotaxane complexes. In addition, the lack of structural flexibility of the recognition units that can form pseudorotaxane complexes hinders the application of unique functions or structures into already practically used materials and/or biologically important (macro)molecules, many of which do not contain the necessary, suitably arranged recognition units in their native molecular structures.